Method of and means for releasing and recovering fast casing from wells



Dec. 29 1925- J. C. SWAN METHOD oF AND MEANS Fon RELEAsNG AND RECOVERING FAST CASING FROM WELLS y? IL M, a z A@ V/ A N\\\\\\\\\\\\\\\\\\NN\ w I4 All' Filed NOV. 27, 1923 Patented Dec. 29, 1925.

`UNITED STATES PATENT OFFICE..

JOHN C. SWAN, OF MARIETTA, OHIO..

METHOD OF AND MEANS FOR RELEASING AND RECOVERING FAST CASING- FROM 1- i WELLS. A f

Application filed November 27, 193. Serial No. 677,351.

fo all whom t may concern: A Be it known thatwI; JOHN C. SWAN, a citizen of the United States, residing at Marietta, in the county of Washington and State of Ohio, have invented certain new and useful Improvements inv Methods of and Means for Releasing and Recovering Fast Casing from/'Wells ofwhich the following is a specification. Y

The invention relates to amethod of and 'means for releasing, starting and recovering a string of casing from the bottom of a well or from such other point in the well at which the casing may be lodged, either by accident, unknown conditions or by deswn.

"By virtue of the use of the present improvements casings may be salvaged under conditions which heretofore precluded the same, or which `permitted of salvaging only in part. s

It is common practice in the cable tool fields of this country to drill .completely through water strata yif possible before inserting a string of casing to exclude it from the well.- To make certain of the exclusion resort is made. frequently to the introduction of clay in the orm of compressed balls which are thrown into the well andallowed to settle to the bottom ofthe well before the casing is iinall landed.

In addition to t is many1 drillers do Vnot attempt to remove a ve large part of the drilling sediment that is 1n suspension in the well water and this sediment after the water has been shutoff finally settles around the lower sections ofthe easing.' When the time comes to remove that casing this condition offers great resistance to starting the casing by the ordinary pulling methods and ver frequently defeats `the purpose altoget er, calling for the use vof casing split- A ters, collar busters and casing pulling trip- By the application of the method and means hereinafter described the foregoing and other difficulties attending the present practice are avoided and it is possible to apply at the point of the well where the o struction tothe movement of the casing is located the degree of force necessary to release the casing. This heretofore has been patent are clear of sand, sediment, etc., but

the casing is frozen to the vis'cid medium and is held so fast thereby that the ordinary hoisting method is not suiieient Ato release the casing. By supplying a heating medium however to the inside of the casing where it is thus held -fast the iilm of viscous material in Contact with the casing may be softened or liquefied and the casing thereby made free at the moment when the lifting force employedA in accordance with this invention is applied. A 4

The desired results are accomplished by the application, upwardly and through suitable mechanical agenoies, of fluid pressure on the casing at or near the lower end thereof; this liftingforce being assisted by the usual casing handling device on the surface of the ground. The casing is thus raised by a simultaneous pushing and pulling operation. Once' released, the casing may be removed from the well by the usual pulling methods. In employing fluid pressure, I may take 4advantage of the hydro- Static head due to the depth of the well, which head of course Vincreases in ratio with the length of the casing to be withdrawn and therefore with its weight; and the fluidpressure .may be augmented as desired by a suitable pump at the top of the well. Either oil, as or water may be used as the fluid, but 1f oil -is available ,and permissible for the purpose I prefer to use this medium.

The invention will better be understood by reference to the accompanying drawing, wherein:

Fig. 1 is a broken sectional view of a well equipped with means for carrying out th invention;

Fig. 2 is a similar view showing the relation of the elements after initial movement of certain of the parts upwardly, and with the gripping means in engagement with the casing; Y

Figs..3 and 4 are views similar ingeneral to Figs. 1 and' 2 butenlarged and ,showing only certain of the parts;

Fig- 5 is a horizontal sectional view on the line 5 5, looking downwardly; and Y Fig. 6 is a perspective view of the suspending sleeve.

In the drawing, thenumeral 10 Iindicates a lower portion of the casing to be removed, shown in Fig. 1 in position in the well. It need not be the lowermost section, and in deep wells may be a portion several hundred feet above the bottom of the well. However, the portion Yreferred to usually will be so far down the string that the bulk of the weight of the casing will be above the same. Within the casing is a pistonelike member having aY headll and an stem 12. The member is provided with a bore 13 which extends longitudinally through the stem 12 and head 1,1 to the lower sur-face of the member. The head 11 occupies substantially the entire inside cross-sectional -area of the casing 10 but it has a sliding fit with the casing.

The upper end of the stem is reduced and left-hand screvv` threads are provided on the reduced portion 14. By means of a coupling V15 the internal left-hand thread of which engages the thread Yof the portion 14.

of the stem, the piston-like member is supported upon and made directly movable with a string of tubing 16 ywhich extends to the top ofthe well. 'lhe`tubing 16 and the coupling 15 may be joined by a righthand thread connection 17. TheYp'iston-like member and its coupling constitute a frame which is comparable to a packer frame.

i Around the upper portion of the stem 12 and abutting against the lower shoulder 18 of the coupling 15 .is a cylindrical sleeve 19. As best shown in Figs. 5 and the sleeve is provided at lits opposite ends with a series of aligned 'pairs of lateral lugs or ears 20. These lugs may, be welded on tothe body of the sleeve 19 or they maybe formed by suitable milling operations, such as are well known in the vart of metal working. A seriesof leaf spring's`21, preferablyfbut not necessarily six in number, are supportedin the respective pairs of ears 20 at the upper end of the sleeve, by means of rivets or the like 22. The lower ends 23 of the springs fall a littlev short of the lower series of lugs and rest on the external .surface of the sleeve. Suspended i lfrom the respective pairs orlower lugs, by means of rivets. or

pivot rods 24, are a plurality of links 425.

To the lower ends 'of the links are suspended vby pivotal connections 26 a corresponding number ofslipsf27 having'external wickers 28 adapted under properconditions toblteinto the inner wall of the casing 10. The innert-portions 29 of the wicker slips are cut awayiat an acute angle with the axis of the casing. This reduction of the inner portions of the wicker slips is necessary Iin order to permit the wicker slips to pass freely downward into the casing; but the more acute the angle between the inner portion of the wicker slip and theoaxis of the casing, the longer will be the available surface of gripping by the wickers. With a view to economy and nlightness the rear edges 30 of the ears 20 are rounded off. By the means described above the Wicker slips 27 are suspended by and from the pairs of lugs 20, through the medium of the links 25 and the springs 21 Which are at all times in frictional contact with the inner wall ofthe casing. It will be readily understood that downward movement of the tubning 16, and consequently the coupling 15,

will be followed by the sleeve 1S), the links 25 and the wicker slips 27. Upon upward movement however of the tubing and coupling and the stem 12 of the piston-like member, the wicker slips will be held against such upward movement by the frictional contact of the springs 21 with the casting.

`Around the stem of the piston-like member and, above the head 11 thereof is suit-V able'packing means intended to be of such eliciency as to seal theY spaceY within the casing 10 above the piston head 11 against fluid under pressure introduced below the head 11. l In a genera1 wayv the packing shown resembles the well packing means' disclosed in my copending application filed February 6, 1923, Serial No. 617,354. As illustrated, the packer comprises a series ol" annuli 31 composed of a metal such as lead which is flowable under pressure the annuli or rings being of arch shape in cross section, with the wall ofthe arch thickeralongy the sides and at the spring than at the periphery or crown. The annuli are spaced apart by ,shallow cylindrical hollow rings 32 which-are made of any compressible material which is strong enough to be selfsupporting under the conditions of use to be described but which may be easily deformed and made to expand or flow toward the casing 10 upon the application of axiial pressure on 'the side walls. Between the annuli 314 andthe cylindrical bodies 32 are preferably interposed steel rings or washers 33. The annuli' 31 and the cylindricall members 32 are filled with a plastic sealing agent which maybe rubber or.-hard coal tar pitch or woodjtar pitch, or it may be a composition of rosin, para'lin and linsed oil.

`Slidably mounted on the stem 12, above vand resting upon Athe uppermost annulus 31,

isa wedge ring 34 tapering inwardly along the direction of the top of the well. At the proper time this wedge memberis moved 1 the wicker slips27 and force the wickers 28 into anchoring engagement with the linner wall of the casing 1(7).

For the purpose of introducing steam, which preferably is super-heated, a pipe or other conduit is supported within the casing 10 and its lower end 36 may terminate in proximity to the coupling 15. At the top of the well a source of steam supply is indicated at 37.

In the use of the zqiparatus described, the piston-like member comprising the packer frame is lowered into the well by means of the tubing 16 to which it is coupled, until the member reaches the region where the casing is held fast. This may be at or near the bottom of the well 'or it may be some distance above the bottoni of the well. For the purpose of illustration it will be assumed that it is the object of the operation to release the casing from a well wall which has been sealed in accordance with the process described in my patent heretofore re to the freezing of the sealing agent to the casing. Proceeding under these conditions, the piston-like member with the sealing means 31, 32, wedge ring 34, wicker slips 27, links 25, springs 21, etc. thereon, is lowered into the Vwell by means of the tubing 16 and coupling 15 until the assembly described arrives at a position as near as possible to the lowermost section of the string. Thereupon the tubing 16 is raised by the same means at the top of the well which has supported the apparatus and lowered it into the well. By this upward movement the lpiston-like member is also raised of course but the wicker slips 27 remain in fixed position dueto the frictional engagement of the spring members 21 with the inner wall of the casing 10. With the piston-like member are also raised the sealing means 31 and 32 and the wedge ring 34. After a predetermined interval depending upon the distance between the wedge ring and the wicker slips, the wedge ring moves upwardly behind the slips as shown 1n Figs. 2 and 4 and causes the wickers of the slips to bite iirmly into the casing. By making the entering angle of the wedge relatively small, as previously mentioned, and by suspending the wicker slips from the sleeve 19 by the pivoted links 25 which, as clearly shown in Fig. 4, have considerable radial play in the casing at their lower ends where the wicker slips are may be of considerab e length and their full range of bite made effective. The swing of the links 25 outwardly, as shown in Figs. 2 and 4, permits the wedge ring 34 to ride behind substantially the entirev length of the wicker slips and thereby to'cause the enivoted, theV wickers gagement of the wickers with the casing along substantially the full length of the slips. The operation so far d'escribed eiiects the gripping of the casing by means which is then movable with the piston-like member in any further travel upward. Further upward movement of the piston-like meniber causes axial compression upon the an# v nuli 31 and the rings 32 and this in turn causes the annuli and rings and the plastic filling contained therein to flow radially outward to make a firm sealing engagement with the inner wall of the casing. In this manner the space within the casing above the head of the piston-like member is eifertively sealed against the passage ther-cinto of fluid under pressure from the space in the .casing or well below the head.

The casing being thus firmly gripped and therefore now substantially immovably connected with the piston like member, and the' casing being effectively sealed against the upward passage of fluid past the piston head' 11, a fluid under very high pressure is admitted to the space below the head 11 through the bore 13. The fluid may be gaseous but preferably it is a liquid. As previously mentioned the liquid may be water, oil or tar, but where available and permissible I prefer to useroil. By using a liquid for the pressure medium advantage may be taken of the hydrostatic head vresulting from the de th of the well which obviously will be conslderable in the present day deep wells where the diiiculty in salvaging casing is the greatest and yet, because of the many tons of metal represented by the casing, is highly desirable. The pressure of the fluid may be augmented by a suitable pump 16 and the bore 13, superheated steam is introduced intoy the well onto the casing through the pipe 35. The heat thereof through the casing causes the congeal'ed sealing agent contiguous to the exterior surface of the casing to become softened or liquefied, so that the casing no longer remains stuck but may readily be removed from the well. By the simultaneous introduction of the heating medium and the liquid under pressure, and atv the same time exerting an upward pull through the tubing 16 by the commonly employed hoisting means, casing may readily be released however tightly the sealing agent p may have been frozen onto the casing.

Referring to the starting of fast casings under the conditions previously described where a viscous sealing agent is not employed, it will be understood that the pressure of the fluid may be raised to such a point that a circulation will be established through the binding sediment referred to,

to such degree that the sediment again will be distributed in the water behind the casing, which always lies above this body of sediment under the conditions stated; in

which case the casing not only will be started upwardly but completely freed to the surface of the ground if desired, making effective the ordinarily used pulling methods for the purpose of casing recovery. Failing in this by the cold application of the method described, the casing may first be heated to expand it against the well wall and then suddenly cooled to contract it by dumping cold water into the casing, in the meantime maintaining the maximum pressure.

Obviously many details of the means illustrated may be modied, and it is to be understood that such changes may be made without departing from the scope of the invention, which scope is restricted only by the limitations in the appended claims.

I claim:

1. The method of releasing well casings which comprises establishing a fluid-tight abutment with a lower portion of the casing, and introducing through the abutment Va fluid under pressure and thereby applying -a head of hydrostatic pressure beneath the abutment.

2. The method of releasing well casings which comprises introducing a piston-like element into the casing, anchoring it substantially immovably to the inner wall of the casing, and passing a fluid under pressure through the piston-like element to exeift pressure upon the lower surfaces thereo 3. The method of releasing well casings` which comprises introducing a piston-like element into the casing, anchoring substantially immovably to the inner wall ci. the casing and rovlding a fluid-tight seal, and passing a uid under pressure through the seal and the piston-like element to exert pressure upon the lower surface of the latter.

wells which have been sealed with viscid, congealable liquids, which comprises applying Huid under pressure to a lower portion of the casing under conditions causing the pressure to be exerted upwardly on substantially the full cross sectional area oif the casing as an abutment, and simultaneously applying heat to the casing in the region o sealing.

5. The method of releasing casing from wells which have been sealed with viscid, congealable liquids, which comprises applying a head of hydrostatic pressure to a lower portion of the casing under conditions causing the hydrostatic head to exert its pressure upwardly on substantially the full cross sectional area of the casing as an abutment, and simultaneously introducing steam into the casing in the region of sealing.

6. Apparatus forreleasing the casings of wells which have been sealed with viscid, congealable liquids, comprising a pistonlike member provided with means afording a sliding fit in the casing and having a bore therethrough, means constructed and arranged to be forced into frictional contact with the inner wall of the casing in response to upward movement of the pistonlike member for anchoring the latter substantially immovably to the wall of the casing, means for introducing a heating fluid against the casing to soften or liquefy the congealed sealing agent in contact with the casing, and means for applying iuid pressure on the lower endv of `the piston-like member.

In testimony whereof, 1 aix my signature.

JOHN C. SWAN.

4. The method of releasing casing from 

